Methyl Bromide: Effect of Multiple Fumigation on Residues in Flour2

Pallet-size plywood containers holding forty-eight 50-lb bags of flour were fumigated with methyl bromide. These fumigations at 15.6, 21.1, and 26.7°C were repeated until the 125-ppm tolerance for inorganic bromide on the flour was reached or exceeded. The inorganic bromide residues increased with an increase in fumigation temperature even though the methyl bromide dosage was decreased. About 3, 4, and 5 methyl bromide fumigations of flour can be made at 26.7, 21.1, and 15.6°C, respectively, without exceeding residue tolerances.